A conventional image forming apparatus generally has functions for storing image data, which is received from an information generating source such as an information processor or document reader, in an image memory, storing the data in a memory upon appending job types and job sequence on a per-file basis, thereby registering the data as print jobs, launching the print jobs one after another and executing them.
The development of advanced multiple functions in image forming apparatuses such as copiers, facsimile machines and printers in recent years has become conspicuous. Furthermore, various management systems for image forming apparatuses that make it possible for such multifunction image forming apparatuses to be utilized by multiple users via a network have been proposed. In one example of such a system, a personal computer serving as a host and an image forming apparatus are connected via a network such as a LAN so that the image forming apparatus, such as printer, can be shared by these multiple users.
If the advanced multiple functions of the image forming apparatus in such a shared system are capable of being utilized without permission by a third party who is not a sharer (namely an outsider), problems can arise in terms of one's share of expenses for consumables and maintenance. In addition, an increase in running cost cannot be ignored at corporations and workplaces where a number of printers have been installed.
On the other hand, there are occasions where general users want to use printers in public printing systems installed in shops in town. For example, it is convenient if a printer in a public printing system can be used when a user wishes to print a print job that is difficult to print out on a household printer or a voluminous print job that would take too much time to print out on a household printer. The reason for this is that a printer in a public printing system generally has functions more advanced than those of a household printer. In such case the user transmits the data of the print job from his or her own personal computer to the public system via a network. However, in a print system that has been installed in a shop, etc., in town, it is preferable as far as the installer who has installed the system is concerned that such printing not be performed when it comes to collecting the fees for the printing service. Further, as far as the user is concerned, if the printed material is output before the user arrives at the location (such as a convenience store) where the printing system is installed, there is the possibility that another person will pilfer the printout or read its content. Accordingly, what is desirable for both the installer who has installed the system and the user is that the user go to the printing system, make payment of the fee at this location and instruct that the print job be printed upon having his or her identity authenticated.
Accordingly, management methods for restricting free utilization of the image forming apparatus have been proposed. Such methods do not allow a third party to utilize the image forming apparatus by permitting only a sharing user to utilize the apparatus, or execute processing to charge the third party separately.
One known method of managing an image forming apparatus by a fee charging function involves having an administrator set, together with an ID number and password, the number of sheets a user can print in a certain period of time, and denying utilization of the image forming apparatus when the number of printed sheets reaches the number allowed. In another known method involving an image forming apparatus to which a fee collecting device has been connected, a fee is charged in accordance with the image forming operation and images are formed up to the limit of the fee that has been introduced into the fee collecting device (see the specification of Japanese Patent Application Laid-Open No. 10-020957).
One proposed method of performing authentication by a portable storage medium and managing restriction of utilization involves waiting for authentication and placing image formation on standby in a case where an authentication card has not been inserted even though the print job has been accepted. Another method involves discarding a received job in the event that authentication has failed (see the specifications of Japanese Patent Application Laid-Open Nos. 11-305968 and 2000-250730).
Another proposed printing system is equipped with an authentication function for enhancing security and with a charging function for collecting a fee in accordance with utilization of a printing apparatus (see the specification of Japanese Patent Application Laid-Open No. 2001-075751).
However, in an image forming apparatus that is managed by such authentication and charging functions, the apparatus will suspend in mid-course a print job whose execution is in progress if a fee insufficiency occurs during execution of the print job. This gives rise to a problem set forth below.
Specifically, the conventional apparatus is such that if a print job is suspended in mid-course owing to a fee insufficiency, the next user cannot utilize the image forming apparatus and the next waiting job cannot be executed. Accordingly, the print job must be resumed by contacting the administrator or by changing to a sufficiently printable number of sheets as by making an additional payment, or the suspended print job must be deleted or saved.
Furthermore, in a case where a suspended print job is being managed by an authentication function, the command to delete or save the print job must be issued by the printing individual who executed the print job. If the print job is terminated while still in the suspended state, another user cannot utilize the image forming apparatus.